KH throttle body rebuilding, parts?

[auditude at neta.com]

Hello all,

I have acquired a KH intake manifold and some throttle bodies for
my EFI conversion onto an MC-1 motor.  I got three throttle bodies
in various states of (in)completion and damage.

I was wondering if the little plastic guide piece that is on the shaft
underneath the return spring is available anywhere.  Is this an item
that has a part number that can be bought separately from the
throttle body?

Or, is there a place that remanufactures these that I could
exchange one or two or all of these for a new one?  I imagine
something like this might be as easy/expensive as going to the
FLAPS.

Perhaps I can get a new one turned out of bronze or aluminum or
some other metal.  Any tips on any of this stuff?

Thanks,

Ken